Translation:The waitresses misheard the numbers, so they miscalculated.
It's after midnight. The room is filled with smoke. A waitress in a blue uniform approaches a table of rowdy sailors and says "how many milkshakes do you want." A black man with wooden eye answers "seven" but she hears "fourteen" and ends up charging the men double.
She dodnt miscalculate wrong there. She calculated right but with the wrong numbers.